Voluminous prior art exists regarding snowguns and snow-making apparatus. The preponderance of artifical snow-making devices, many currently in use, operate on the principle of combining (internally) compressed air and water and further, conducting the mixture to nozzle means for atomizing and ejecting it into the ambient air. What at first glance would appear to be a rather simple process is clearly contraverted by the fact that there has been so much past and current activity related to the development of inventions such as the instant one.
Throughout the history of artificial snow making, three major concerns have driven numerous inventors to search wide ranging scientific arts to acquire the ability to: (1) vary the size of the artificial snow crystals; (2) increase the throw trajectories obtainable from traditional nozzles, (given constant pressure fluids); and (3) enchance the overall quality of snow crystal in relation to the type of pack required on any given ski slope. Constantly iterating any development equation drawn to the aforementioned concerns are perhaps more numerous subfactors: the size of a snow crystal is dependent upon ambient air temperature, mixture temperature and exhaust pressure that affect the degree of atomization; throw trajectory is affected by fluid pressures, nozzle geometry and, as specifically addressed in this application, the presence or absence of physical inhibitors such as rime ice forming on the spray heads; and, quality of the snow crystal is dependent upon most of the foregoing factors as well as ambient (outside) air temperatures.
A patent issued to Smith in 1979, U.S. Pat. No. 4,145,000, disclosed a snow-making nozzle assembly which had the purpose of producing uniform, highly atomized droplets of liquid that would freeze in the ambient air to form snow. This invention was concerned primarily with the size and quality of the snow crystals formed; and, the particular nozzle teaching that it embodies is the use of a convergent-divergent compressed air nozzle which, at the diversion portion, entrains water that is inducted at opposed pairs of water outlets spaced at the periphery of the generally fan-shaped convergent-divergent compressed air nozzle. Because of the use of a large quantity of compressed air, this invention appears able to avoid the consequence of rime ice formation at the nozzle exhaust. The consequence of such a device, however, is that additional cost must be expended to provide the high volume of compressed air. To those familiar with the snow-making art, the high cost of compressed air is perhaps the most onerous burden which must be borne.
In 1969, Carlsson was issued U.S. Pat. No. 3,464,625 for a method and means for making snow. This invention combines ejector art with the physical principles of the convergent-divergent nozzle and achieved a satisfactory product of somewhat limited quantity. Carlsson's use of the ejector literally allowed him to develop a device for entraining an annulus of air by a column of water which passed through the center of the air annulus. Since the entrainment principle works best with miscible fluids (such as water and air), Carlsson was able to achieve a quality snow crystal. The disadvantage presented by this art, however, is that the sudden cooling in the divergent section of such a nozzle, especially of the length disclosed in the patent, gives rise to an icing condition which may occur actually within the divergent nozzle. Such icing interfers significantly with the throw trajectory of the snowgun.
In searching diverse art (for analogous features), U.S. Pat. No. 1,529,562, Which was issued to Vezie in 1925 disclosed a Superheating Oil Burner which by a novel combination of a closed cylinder Within a cylinder provided a means whereby liquid fluid (oil) could be heated by gaseous fluid (steam) using the principle of the heat exchanger. As in most of the snowgun art, the gaseous fluid of this invention was used to expel the liquid fluid; nonetheless, this principle, in an earlier pristine form, spurred this inventor to further research and development of the instant invention.
Superficially, patents issued to Ash and Fairbank, U.S. Pat. Nos. 4,465,230 and 4,275,833 respectively, would appear to repeat the art of Vezie. As a closer reading of these patents reveals, however, the inventors are driving a stream of water coaxially through a port in the side of closed cylinder of highly compressed air. Both inventions are apparently avoiding the mixing of the fluids by what Ash terms to be the injection of a column of water (centrally) into a column of air and, in so doing, effect a laminar flow therebetween. In the view of the instant inventor, a most serious disadvantage attends this form of art in that if they attain a laminar flow, the inventions do not mix the fluids (water and air) and therefore failing to achieve any significant control over the degree of atomization, the quality of the snow crystals cannot be varied. Further, in the instant inventor's experience, this apparatus, because it has no designed anti-icing features, suffers from icing and dimished throw trajectory, as does all the prior art.
Although different methods of atomization exist, with varying degrees of efficiency, the primary defect inherent in all of the prior art related to snow-making devices and guns is the inability of these devices to prevent rime icing, at the nozzle, ejection ports or in snowgun heads, at temperatures below 25 degrees Fahrenheit. As ambient temperatures fall below 25 degrees Fahrenheit, the devices of the prior art "ice up" creating a number of problems: (1) the snowgun ejection nozzle becomes partially blocked thus perturbing the throw trajectory; (2) the blockage of the nozzle eventually disrupts the constantcy of snow quality; (3) constant supervision is required to prevent or aleviate these icing conditions; and, (4) freezing of the moisture content of the air inside the snowgun head makes the apparatus inoperable.
The present invention, drawn to and developed to quiet the industry's concerns, combines older, unused principles with novel developments by the inventor and, in so doing, avoids the aforementioned disadvantages.
Through numerous experiments, and the development of devices that have been tested on extant ski slopes in the northeast United States, the inventor determined that the nexus of the aforementioned problems and disadvantages was the inability of the snowmaker to control the temperatures of the fluid ejecta and thereby avoid icing conditions. Since most water used is taken from below grade, its temperature is generally at around 56 degrees Fahrenheit. Air however, having been already compressed, is (already) at ambient temperature. Admittedly, the cooler air would indicate a drier fluid and therefore greater solubility in water; however, such a factor remains more dependent upon the water temperature. The inventor initially reasoned that if the air were warmed slightly, say to water temperature, the admixture of the two fluids were forced (i.e., a forced mixing), and the ejecta solution were expelled into the colder sub-freezing atmosphere, it would be possible to achieve a generally good quality snow using less compressed air and suffer no icing at temperatures below zero degrees Fahrenheit. The instant invention, hereinafter described, achieved these objectives, and more. Production of this invention, as may be readily ascertained by one of ordinary skill viewing the drawings and reading this disclosure, has been embodied in but a few machining and welding processes and results in a most inexpensive and trouble-free product.